This invention relates to lined plug valves and, more particularly, to plug valves which include a liner of lowfriction, resilient material to provide a seal between valve body and plug and, in addition, to facilitate turning of the plug. The material most commonly used in such plug valves is polytetrafluoroethylene (PTFE) and considerable difficulty has been experienced in seal retention, primarily because of the lack of elasticity of PTFE which makes is deform under differential pressure. Hence, the material tends to bend into the valve passageway under flow forces whereby it may be severed by subsequent rotation of the valve plug.